Which jet was better, the Me 262 or the Gloster Meteor? (1 Viewer)

[GrauGeist]

Udet wasn't all that impressed with the He280 (or anything with jet engines, for that matter)...had Udet or any of the RLM leaders approved of the jet programs that were going on before or during the early stages of the war, much needed funding (and resources) would have been available for engine development.

As it was, Heinkel (along with the other engine developers) were primarily funding these projects out of thier pockets and development suffered terribly.

 

[Magnon]

On 7 November 1945, a Meteor F3 powered by Derwent Vs set a world air speed record of 606 mph (975 km/h) TAS. The Me262 was well and truly unstable at this speed. Refer to the Me 262 A-1 Pilot's Handbook:
"...Speeds of 590 mph are reported to have been obtained in a shallow dive 20 to 30 degrees from the horizontal. At speeds of [590 to 620] the air flow around the aircraft reaches the speed of sound and it is reported that the control surfaces no longer affect the direction of flight. The results vary with different airplanes; some wing over and dive while others dive gradually..."

 

[Erich]

you cannot make any viable comparison to speeds with the Nov. 45 date Magnon. did you know completely revamped engines and redesigned swept back wings and streamlined body were to be fitted to just the night fighter version of the Me 262 in July of 45 had the war lurked onward ? ........ so with that we can only guess what the crate would of attained and also what of the day fighter version had it be re-assesed as it was in the spring of 45.

maybe it would of flown at 600mph plus but we will never know

 

[Magnon]

Yes, and other changes were mooted too:
"Since the long nose of the Me-262 led to poor pilot visibility, reconnaissance and bomber variants were proposed with the cockpit moved well forward, giving the aircraft something of the look of the Gloster Meteor."
The Messerschmitt Me-262 Schwalbe / Sturmvogel

 

[GrauGeist]

Interesting site, Magnon, but that page has a number of errors. The author also tends to put in speculation where they're lacking info...

As far as the Me262 HG goes, it was the design Willy Messerschmitt wanted for the next step in the Me262's evolution.

 

[Magnon]

'At a conference summoned by Göring two days later, 'to clarify things once and for all', Professor Messerschmitt and even Petersen blamed the absent Milch for the misunderstandings which had arisen. Göring announced that he was transferring the project from Galland's office to that of the General of Bombers, 'to avoid further errors'. When Petersen admitted that the jet engine had a tendency to 'flame out' above twenty-eight thousand feet if throttled back to reduce speed, Göring triumphed, 'Then I can only say, the Führer was right again, with his brilliant and instinctive touch!' And when Professor Messerschmitt began to explain how, after releasing its bomb, the Me 262 was just like a fighter again, Göring anxiously interrupted, 'Not like "a fighter" again, but "super fast" again. Stop calling it a "fighter"!'
(The Rise and Fall of the Luftwaffe)


Lions led by jackasses...

 

[Magnon]

_______

 

[Magnon]

From the same source:

...Hitler summoned the seven top aircraft designers to the Obersalzberg and interrogated each in turn. Heinkel now displaced in his own factory by a government 'Kommissar' excused his He 177's tardiness by the 'hitherto unshakable requirement that it should dive-bomb' (although Göring had emphatically removed this requirement ten months before). Messerschmitt's contribution to Hitler's state of mind was even more remarkable. For an hour he heaped criticism on Milch, and actually warned Hitler and Speer who chanced to come in against the folly of mass producing the Me 262 fighter, since its fuel consumption was, he alleged, higher than that of piston-engined fighters like the Me 209 which Milch in his sublime ignorance had now cancelled. Thus at the very time that Milch was campaigning for priority for the jet fighter, its own designer was sowing the seeds of doubt in Hitler's mind...

 

[Magnon]

'...In fact, Hitler had strong doubts whether the Me 262 fighter version would really be of any use against the Allied fighters, which alone were the guarantee of enemy air supremacy. He believed the jets would find it tactically difficult to engage the far slower but more agile piston-engined Mustangs and Thunderbolts; the enemy would only have to curve and the jet would overshoot him. (This fear was to prove well-founded. In combat the Me 262 fighter's chief success was to force the American long-range escort fighters to jettison their fuel tanks, which obliged them to turn back early; actual combat victories by the jet fighters were disappointingly few.) Göring pledged that every man working on the aircraft would now honourably try to achieve what Hitler ordered. On 27 May he telegraphed Milch emphatically: 'The Führer has ordered that the Me 262 aircraft is to enter service exclusively as a high-speed bomber. The aircraft is not to be regarded as a fighter until further notice...'
The British had thought about assassinating Hitler earlier in the war, but thought better of it because they realised he was their greatest asset.

 

[Magnon]

The Me 262 Project gives a good opportunity to assess some of the design problems with the Me 262:

"As the landing gear was known to be another weak area on the original Me 262, a detailed analysis of landing gear stresses was directed. This process revealed that a shock loading was generated by the spin-up forces of the large, heavy main wheels, which had to be reacted into by the wing landing gear attachment structure. This placed a severe demand upon wing spar area and the airframe simply had to absorb these forces. Over time, this would have had a devastating effect upon the aircraft.
In part, this problem can be traced to the history of the aircraft. As originally designed, the Me 262 was equipped with a standard tail wheel (in lieu of the nose wheel).
In the tail-dragger configuration, the main gear was bolted directly onto the wing spar; however, the tricycle modification resulted in the creation of a separate wing torque box to be used as a mounting point. This torque box was susceptible to damage, and very difficult to repair."​

This is substantiated by the Me 262 A1 Pilots Handbook:

"In case of a very short flight in which fuel has not all been used from the auxiliary tanks, use caution in landing as the allowable landing weight is exceeded due to fuel load..."​

 

[Magnon]

From ME262 Stormbirds at War

Even this pro Me262 site admits some crucial failings in the Schwalbe:

One of the many problems the design had to live with was that the materials necessary for proper heat proofing for the Jumo engines were extremely rare in war-torn Germany...

[That's a myth. They allocated plenty of nickel to the armour plating of an amazing fifty thousand tanks during the war, averaging around fifty tonnes each, including Tigers, Panzers I to V, and Elefants. If we assume that 40% of the tank mass is armour, that still gives around a million tonnes of armour. The armour plate had around 4.5% nickel content, representing 45,000 tonnes of nickel. A thousand tonnes would have been more than adequate for a Me 262 program of two thousand aircraft. With two thousand reliable and efficient jets (which the Me 262 wasn't) at the core of the Luftwaffe, it could have been invincible. Air superiority would have been assured and the enemy armies would be going backwards leaving behind abandoned tanks which could be recycled for more nickel. Have I missed something here?]

...(as a result) alternate materials had to be used which resulted in engines that were less than reliable. Many times a brand new engine would suffer catastrophic failure during initial run-up. Even the "good engines" might only last for 12 hours of operation. And as General Galland himself remarked concerning the performance of the 262; "As a negative consequence, the war would most probably have been prolonged, and the Russians allowed more time to conquer further German territory. So let us now be satisfied with Hitler's mistakes towards the legendary Me 262."
About.com: http://www.stormbirds.com/warbirds/history1.htm

 

[Magnon]

[Hans Fey, Messerschmitt test pilot and technical inspector] says that the structural workmanship on the Me 262 is not as good as that on the Me 109. When testing the Me 262, it was not infrequent for parts to be stripped off in fast, steep dives and Fey has himself lost cockpit covers, bomb racks and the needle valve [read variable area nozzle] of the tail pipe during dives. In fact, because of these uncertainties, the pilots rarely did a roll or similar maneuver during acceptance flights...

Me262pilotdebrief

 

[Magnon]

Approach and Landing:

"

​

The landing approach is made at 250 km/hr (155 mph). Use flaps as needed and carry 6000 – 7000 rpm so that the throttle can be opened quickly in case of a go-around."

​

"Note: If rpm is less than 6000, any advance must be made slowly to 7000 before opening wide. The airplane stalls at 112 to 125 mph."

Me 262 Pilot's Handbook

​

This sounds problematical to me! Does anyone know if the pilots who flew this thing got some sort of stress allowance? Maybe they should have just automatically been awarded the Iron Cross when they climbed into the cockpit.

The Schwalbe needed to maintain relatively high thrust when landing because the engine would disintegrate if you had to rapidly accelerate from below 6000 rpm... At 6000 rpm, the engine was still developing about 40% power. Again, the Schwalbe had no air brakes... The Meteor did...

See Ken Holt's narrative to get a feel for the problems. Arrival: Operations at Newark

Note that, all things being equal, the stress on the landing gear is a function of the square of the landing speed. See how the two aircraft compare in this regard:


Meteor Stall speed 105 mph Landing speed 125 mph
Schwalbe Stall speed 112 - 125 mph Landing speed 155 mph

On the basis of the above "rule of thumb," the Schwalbe landing stresses would have been around 50% higher than that of the Meteor. However, as mentioned in a previous post, due to a change from tail wheel to tricycle undercarriage without adequate design rigour, the effective structural stresses were much higher again. Aluminium is unforgiving in terms of being subjected to heavy repeated loads. With the overload stresses being transmitted up to the wing from the undercarriage, it's only a matter of time before a wing gives way as you are trying to pull high Gs in a turn. But as someone said in one of the previous posts, the Me 262 service life was accepted as only having to be about ten hours anyway...

"In case of a very short flight in which fuel has not all been used from the auxiliary tanks, use caution in landing as the allowable landing weight is exceeded due to fuel load..."
Me 262 A1 Pilots Handbook

That's a masterpiece of understatement...

This whole problem is confirmed by another source:
"...The landing gear was also suspect, and many 262s were destroyed or damaged due to landing gear failure."
http://www.military-art.com/mall/aircr

​

aftinfo.php?AircraftID=116

Further, because of their problem with the combination of the need for high landing speeds and the badly designed undercarriage, the Schwalbe tended to be limited operationally to concrete runways. Hence the Allies targeted these as being the zones where the Schwalbe was most vulnerable. At such a low level, when an aircraft was taken out, so inevitably was the pilot. There weren't enough experienced pilots around to be able to afford to lose them as rapidly as they did. And only experienced pilots could hope to handle the Me 262. With a more capable aircraft, the Germans would have been able to disperse to a large number of small grass strips which would be hard to detect and thus target. In this regard, it's been documented that a Meteor once landed in a ploughed field, refuelled, and took off again.

 

[Magnon]

BRAKE SYSTEM IMPROVEMENTS

The braking systems of wartime German aircraft usually left something to be desired, and the Me 262 was no exception. Brake fading and/or complete system failures were a common complaint. (For a brief description of such an incident in American hands, see Ken Holt's narrative on the Watson's Whizzers pages.)
The notoriously ineffective nose wheel brake has been eliminated altogether, although the original brake lines will be duplicated for appearance. Meanwhile, the marginally performing drum brakes on the main gear have been replaced by a cleverly-integrated disc brake system.

 

[Magnon]

...Which was best? An axial compressor could achieve a higher efficiency under ideal conditions. It would have a smaller diameter, resulting in lower frontal area, lower blade tip speeds and the opportunity for an annular combustion chamber. Against this, it would be mechanically less robust and aerodynamically much more sensitive to both intake conditions and downstream pressure changes, such as those induced by rapid throttle movements. Both these could lead to blade stalling and resulting surges, which could in turn produce catastrophic blade failures. Pressure increase per row of blades was low, requiring at least eight rows with intermediate stator blades. A centrifugal compressor would be simpler and cheaper to produce, would be more rugged and much more tolerant of the varying intake conditions and throttle changes encountered by a flight engine. It would need to run at higher speeds but there was the extensive experience of small centrifugal compressors developed as aero-engine superchargers, whilst there was little prior art on axials...
...what would be the choice now, with all that is known of both axial and centrifugal compressors, if one was designing an engine to produce around 2,000lbs thrust, as those early designers were? An example is the Rolls-Royce Williams FJ44-2, an engine of 2,300lbs thrust currently produced for business jets. A fan engine (an idea also first patented by Whittle) it has a 3 stage axial (including the fan) driving a centrifugal compressor. Without the fan, this corresponds to Whittle's original turbo-jet patent of 1930. The axial/centrifugal arrangement (or a centrifugal on its own) is still the most common configuration in small engines, the blades of an axial becoming too small for the later stages.
Welcome to the Frank Whittle Website

 

[Magnon]

JUMO Engine
"In aircraft applications, engine power is characteristically measured in terms of thrust versus weight. The Jumo 004 was typical of early jet engines in that it was rather heavy, and not especially efficient."

[The thrust to weight ratio was much inferior to that of the British engines; just over half]

"Production models produced 1,980 lbs. of thrust, and weighed in at about 1,800 lbs. Because of this, the engines were not extraordinarily effective at low airspeeds or altitudes or at reduced power settings."
"Long takeoff rolls (>3,000') were evidence of this phenomenon and, once aloft, power management became critical. Abrupt throttle changes or rapid maneuvering often resulted in a flameout, or worse, a complete compressor failure.""...The [use] of inferior metals compounded an already problematic situation with the turbine blade design. These blades were rigidly mounted, contributing to severe root stress relief problems. The weaker metals simply could not withstand this kind of abuse and regular compressor failures were an inevitable consequence..."
Me 262 PROJECT TECHNICAL DATA

 

[Glider]

Magnon
You seem to be ignoring the one indisputable fact that the Me262 was a whole generation ahead of the Meteor in aerodynamics.
Also the Meteor was going through a considerable number of developments to resolve issues with lack of power and aerodynamics.

 

[Magnon]

The "swept wing" was adopted to allow for a centre of gravity problem:
See ch11-2 -
"According to reference 141, the wing was swept back slightly to position the wing aerodynamic center in the correct relation to the airplane center of gravity..."

Ref 141 is Boyne, Walterj.: Messerschmitt Me 262, Arrow to the Future (Washington: Smithsonian Institution Press, 1980).

Further from the NASA publication:
"...Although a strictly subsonic aircraft, the Meteor did have high performance for a straight-wing fighter; it was rugged, versatile, and capable of being readily adapted to various missions. An interesting account of the development and operational history of the Meteor may be found in reference 188."

Ref 188 is Shacklady, Edward: The Gloster meteor (MacDonald Aircraft Monographs, Doubleday Co., 1963).

If the Schwalbe was so advanced, why did it then have a lower limiting Mach number than the Meteor?

 

[Magnon]

The Jumo 004 had a maximum shaft rpm of 8700 for five minutes duration for takeoff or a maximum ten minutes at "military" [read emergency], with a maximum continuous rpm of 8400 (refer to the Me 262 A-1 Pilot's Handbook). Note that the Schwalbe only reached its maximum rated speed of 515 mph under the emergency rating; hence they had only ten minutes endurance at that speed. Once the military rating had been utilised for the allowed length of time, the engines were required to be taken out of service as soon as possible to undergo rigorous inspection of the rotating components.

The Derwent had a maximum rating of 16,500 rpm for takeoff with 15,000 for cruise. It idled at 6000 rpm! The stress in the turbine blades, assuming they're the same diameter, is a function of the square of the rotational speed. On this basis the relative stress in the Derwent blading was around 360% that of the Jumo.

In spite of this far higher stress in the jet engine's most critical component, the endurance of the Derwent in service was over ten times that of the Jumo. The use of Nimonic 80 made the crucial difference. The Germans didn't have it, and without it, going down the track of developing a reliable and rugged centrifugal compressor was never an option for them. The centrifugal compressor was much less prone to "surge" or blade stall than the axial flow type. When surge occurs, the airflow delivered by the compressor drops drastically while the same fuel flow continues. The result is overheating and catastrophic failure of the turbine blades. Refer to the Me 262 Project feedback:
"Abrupt throttle changes or rapid maneuvering often resulted in a flameout, or worse, a complete compressor failure."
Me 262 PROJECT TECHNICAL DATA
The British developed the axial flow Metrovick engine (first bench tested in 1941) in parallel with the centrifugal Derwent and Goblin types, and this engine was actually trialled in the Meteor. However, as with the German axial flow engines, they were found to be inferior in terms of reliability at the time and hence didn't find application until after the War as the Bristol Siddeley Sapphire. Armstrong Siddeley took over Metrovick's jet business at the end of the war.

The jet engine needs a very high air/fuel ratio of up to 200:1 in order to keep the combustion temperatures down and not destroy the turbine blades (this is around ten times as high as that for a reciprocating engine). So in fact it's essentially "air-cooled" by its own combustion air. On the other hand, in combat, you sometimes need to accelerate in a hurry. That means a big temptation to pour in the fuel, with a consequent high risk of damage to the engine. Hence the Meteor with its high temperature componentry had a crucial advantage here.

Any military man worth his salt will say: "don't give me equipment which is so-called 'state-of-the-art' but liable to fall apart in the heat of battle. I want simple, well-proven, rugged technology which I can rely on to work." Of course this is true for both the airframe and the engines. For the engines, it was certainly a crucial difference between the British and German technology at the time. Apart from this, however, there were other advantages in terms of things like efficiency, lower vulnerability to gunfire and much higher thrust to weight ratio.
Derwent I vs. Jumo 004

Overall pressure ratio: Derwent 3.9:1
JUMO 3.14:1

Engine Thrust Weight Thrust/weight Max. Eng. Speed (rpm)
JUMO 004B : 1980 lb.f: 1800 lb: 1.1:1 : 8,700
JUMO 004D : 2315 lb.f: 1800 lb: 1.3:1 : 10,000
Derwent IV : 2400 lb.f : 975 lb : 2.4:1 : 16,500

Specific Fuel Consumption:
Derwent I 1.17 lb/lbt/hr
JUMO 004B 1.39 lb/lbt/hr
(The Derwent IV specific fuel consumption was similar to the Derwent I. The efficiency was thus around 19% better than that of the JUMO, principally due to the higher pressure ratio.)

The specific fuel consumption figures for the two engines were obtained from
http://www.havovwo.nl/vwo/vna/bestanden/vnaskpwsstraalm.pdf

 

[Glider]

The "swept wing" was adopted to allow for a centre of gravity problem:
See ch11-2 -
"According to reference 141, the wing was swept back slightly to position the wing aerodynamic center in the correct relation to the airplane center of gravity..."

Ref 141 is Boyne, Walterj.: Messerschmitt Me 262, Arrow to the Future (Washington: Smithsonian Institution Press, 1980).

Further from the NASA publication:
"...Although a strictly subsonic aircraft, the Meteor did have high performance for a straight-wing fighter; it was rugged, versatile, and capable of being readily adapted to various missions. An interesting account of the development and operational history of the Meteor may be found in reference 188."

Ref 188 is Shacklady, Edward: The Gloster meteor (MacDonald Aircraft Monographs, Doubleday Co., 1963).

If the Schwalbe was so advanced, why did it then have a lower limiting Mach number than the Meteor?

You seem to be a little selective in the quotes you are posting. Oother quotes from ch11-2 includ

i) Some increase in critical Mach number, however, probably resulted from the 18.5 leading-edge sweepback.
ii) In addition to improving takeoff and landing performance, the slats improved the high-g turning capability in maneuvering flight.
iii) The Me 262 seems to have been a carefully designed aircraft in which great attention was given to the details of aerodynamic design. Such attention frequently spells the difference between a great aircraft and a mediocre one.
iv) As compared with the German fighter, the Meteor was characterized by both higher wing area and drag area.
v) The paper compares the Me262 woth the Meteor IV a post war development of the Meteor.

Last but by no means least, the test pilot Eric Brown who was in the unique position of having flown all the war time jet aircraft, Meteor, Me 262, He 162, Arado 234 and P59 definately preferred the Me262 to the Meteor.